Another interesting plotline could be Sirius taking control of his own fate which was so often dictated by others in the original story. He might discover new magic or form unexpected alliances that help him break free from the chains of his past and the expectations placed on him. He could then use this new - found control to change the course of events in the wizarding world for the better.
Perhaps in the fanfiction, Sirius takes control of a group of misfit witches and wizards and turns them into a powerful force for good. He could be training them, leading them on secret missions and such. It might involve him using his Gryffindor courage and his own unique experiences to guide the group.
One possible plotline could be Sirius taking control of a difficult situation within the wizarding world, like dealing with dark wizards. Maybe he uses his skills and knowledge to outwit them.
Obviously, Sirius Black is the main character. But there could also be other characters like Harry Potter, as Sirius has a strong connection to him. His friends from Hogwarts days might also make an appearance, such as James Potter in flashbacks.
One interesting plotline could be Harry Potter taking control of Hogwarts' curriculum. He might introduce new and more practical magic courses. For example, he could start a course on modern magical defense against dark forces in the wizarding world today, which includes dealing with new threats like dark wizards using Muggle technology in their spells.
Some fanfictions explore a scenario where Marlene survives the war and she and Sirius get a chance to rekindle their relationship. It delves into how they deal with the trauma of the war and their past feelings for each other. They might have to face the judgment of the wizarding society which has changed after the war. This plotline can be very emotional and complex as it involves a lot of character development and exploration of post - war wizarding world.
One common plotline is Sirius Black escaping from Azkaban earlier and secretly training Harry in advanced magic. Another could be Sirius and Harry going on a hidden adventure to uncover more about Harry's parents. There are also stories where Sirius plays a more active role in the fight against Voldemort at Hogwarts, using his knowledge of the Dark Arts and his Animagus form to their advantage.
In some 'sirius black after azkaban fanfiction', there could be a plotline where Sirius has to deal with the stigma of being an escaped convict, even though he was wrongly imprisoned. He might face distrust from some in the wizarding community. At the same time, he could be on a journey to find out who really betrayed his friends all those years ago, which leads him on an adventure full of mystery and danger.
One interesting plotline could be how Sirius helps Harry discover more about his parents in a more personal way. Since Sirius was James Potter's best friend, he could share countless stories and memories that Harry never knew. Another plotline might involve Sirius teaching Harry some advanced magic that he wouldn't learn at Hogwarts. This could give Harry an edge in dealing with the various threats he faces. Also, their relationship could be explored in depth, showing how Sirius becomes not just a guardian but also a true father figure to Harry.
Well, one plotline could be Sirius getting into an argument with another character and saying 'and shut up' in a moment of anger. Maybe it's with Snape and it leads to a whole confrontation that reveals some long - hidden secrets between them.
One great fanfiction where Sirius Black takes care of Hermione could be 'The Guardian'. In this story, Sirius steps in when Hermione is in a difficult situation at Hogwarts. He becomes like a mentor to her, protecting her from the threats of the dark forces that are starting to lurk around the school. He teaches her some advanced magic that she wouldn't have learned otherwise.
One interesting plotline could be Narcissa and Sirius having to team up against a common enemy in the wizarding world. Maybe there's a dark force threatening both the Black family's reputation and Sirius's fight for justice. They start off distrusting each other but gradually learn to work together.
One interesting plotline could be a mystery - solving one. Harry discovers some strange artifacts in Grimmauld Place that were left by Regulus. With Sirius (if he's alive in the fic), they try to figure out what these artifacts mean and it leads them to uncover a long - forgotten plot by Voldemort. Another plotline could be a redemption arc for Regulus. Harry, after learning about Regulus's attempts to undermine Voldemort, tries to clear his name in the wizarding world, which causes some friction with those who still see the Black family as mostly dark wizards. And there could be a plotline about family secrets. Sirius and Harry find out that there are hidden magical abilities in the Black family bloodline that only Regulus knew about, and they have to figure out how to use or control them.